<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>04_作用域_面试题</title>
</head>
<body>
<script type="text/javascript">
 	function wrap(){
 		var a=b=2;
 		var c,d=2;
 	}
	wrap();
//	console.log(a);
	console.log(b);
//	console.log(c);
//	console.log(d);
</script>
</body>
</html>